Ordinary polymers, based upon pure non-polyenic acrylates or allelic monomers, do not have water-solvent ionic layers on their surfaces which are buffered against the sorption of proteins. Providing water-solvent ionic layers on the surface of the polymer is desirable because such layers will greatly improve the bio-compatibility of the lens with cell membranes of the recipient's eye.
Polyenic water-solvent ionic monomers may be used in order to produce a water-solvent layer. However, this decreases the resistance of such copolymers against swelling. For example, the system of polyenic copolymers, based upon acrylamid or acrylic acid with HEMA has a tendency towards excessive swelling beyond all bounds. This happens because pure homopolymers, polyacrylamide or polyacrylic acid, contained in this system, dissolve in water. Therefore, it is an advantage to produce a polymer which would be able to form such a vital water-solvent layer, and would not affect the polymer resistance against swelling.
References concerning graft-copolymers of collagen include U.S. Pat. No. 4,388,428 (Jun. 14, 1983) and U.S. Pat. No. 4,452,925 (Jun. 5, 1994). In these patents, a system of water-soluble monomers and A telo-collagen is used. However, this system is not hydrolytically stable and is not sufficiently optically transparent. In U.S. Pat. No. 4,452,925, nothing is mentioned of special optical conditions needed for transparent polymer production. The water-solvent A telo-collagen disclosed in this patent does not have the capacity to form a gel in the organic monomer solution, and therefore the collagen precipitates or coagulates.